Machine for canning foodstuff product, such as tuna fish and similar

ABSTRACT

A canning machine for a foodstuff product ( 2 ), such as tuna fish and similar, comprises a conveyor belt ( 1 ) suitable for carrying the foodstuff product ( 2 ) in a compressing and shaping device comprising a knife ( 11 ) suitable for cutting substantially parallelepipedal portions ( 12 ) of the foodstuff product ( 2 ) and a compression channel ( 7 ) closed at one end by means of a shaping member ( 8 ) and at the other end by means of a compactor ( 9 ) slidable in the compression channel ( 7 ). Two openings ( 14 ) are made in the bottom wall of the compression channel ( 7 ) in order to allow the passage of a pair of dies ( 16 ) and of a pair of ejecting pistons ( 15 ) which in their initial position close said openings ( 14 ) without substantially protruding into the compression channel ( 7 ). Said ejecting pistons ( 15 ) are capable of a cyclic movement comprising a backward movement with respect to the compressing and shaping device, a forward movement through said openings ( 14 ) and a movement of return to the initial position.

[0001] The present invention relates to an improved canning machine, andparticularly it relates to a machine suitable for shearing, shaping andcanning a foodstuff product such as tuna fish and similar.

[0002] It is known that canning of tuna fish presents a number ofproblems due to the intrinsical nature of this foodstuff and above allto the irregular consistency thereof, which makes it necessary tocompress it in order to bring it to a predetermined density andtherefore to maintain within acceptable limits the weight of the productintroduced into each can.

[0003] Machines for cutting, compressing and canning tuna fish arealready known. For example, patent U.S. Pat. No. 5,203,141 in the nameof the same applicant describes a machine wherein the portions of tunafish obtained by cutting the product are pushed into a compressionchannel which is closed at one end by means of a shaping member providedwith two semi-cylindrical concavities. The portions of tuna fish whichare subsequently compacted against said shaping members are sheared bymeans of two dies, thus forming pairs of cylindrical cakes. These aretransferred inside cans or tins by means of ejecting pistons which enterthe compression channel by passing through suitable openings provided inthe bottom wall of said channel. In their rest position, said ejectingpistons are already partially inserted into said openings and closethem, thus avoiding that the foodstuff product comes out of the channelitself while it is subjected to the compressing and shaping steps.

[0004] However, a problem of said known machine consists in that thetuna fish cakes which can be obtained by using it are characterized by apoor surface quality. As a matter of fact, the pressure exerted on thetuna fish portion during the shaping step of the cakes causes thefoodstuff to stick to the walls of the compression channel, andparticularly to the surface of the ejecting pistons. At the moment ofdetaching the cakes from the pistons, some fibers of the foodstuffproduct stick to the pistons themselves. As a result, the surfaces ofthe so obtained cakes are imperfect; further, the ejecting pistons areencrusted and cannot be cleaned unless the machine is stopped.

[0005] Object of the present invention is therefore to provide a machinewhich is free from the following drawbacks. Said object is obtained by amachine whose main features are specified in the first claim and otherfeatures are specified in the following claims.

[0006] An advantage of the canning machine according to the presentinvention consists in that it allows to prevent the sticking of thecakes to the ejecting pistons and therefore to improve the surfacequality of the cakes. As a matter of fact, the ejecting pistons thereofare capable of a cyclic movement comprising a backward movement withrespect to the compression channel in the moment when the excessivepressure exerted on the tuna fish cakes would cause the above mentionedundesired sticking.

[0007] Further advantages and features of the machine according to thepresent invention will appear to those which are skilled in the art fromthe following detailed description of one embodiment thereof withreference to the only FIG. 1, which shows a perspective simplified viewof the central nucleus of the machine according to said embodiment ofthe invention.

[0008] With reference to said FIG. 1, there is shown that the machineaccording to the present embodiment of the invention comprises in aknown way a conveyor belt 1, suitable for carrying a foodstuff product2, for example tuna fish, through an opening 3 of a compressing andshaping device, wherein the foodstuff product is brought to the densityrequired. Said compressing and shaping device comprises a front block 4,a back block 5 and two side members 6 which connect said front and backblocks and form the side walls of a compression channel 7 positioned inthe middle of said device. The compression channel 7 is closed at oneend thereof by means of a shaping element 8 and at the other end by acompactor 9, which slides in the compression channel 7 under the thrustof a pneumatic piston 10.

[0009] Once crossed opening 3, the foodstuff product 2 is cut by meansof a knife 11 which provides a portion 12 of tuna fish, which isinserted into the compression channel 7 in order to be brought to thedesired density. Knife 11 shown in the figure is of the type with twoopposed blades, but it can be of any other type suitable for thispurpose.

[0010] Tuna fish portion 12, which has a substantially parallelepipedalshape, is pressed by compactor 9 against shaping element 8. Said shapingmember 8 has a substantially flat bottom, with a separating wedge 13 atthe center thereof, suitable for dividing portion 12 of tuna fishsubstantially in two parts. Separating wedge 13 is advantageouslyprovided with an enlarged base through which it is connected to shapingmember 8, and has side profiles which are suitably arched as quarters ofa circle. On the bottom of the compression channel, at the sides ofseparating wedge 13, two openings 14 having circular shape are provided.During the compressing step, said openings 14 are closed by means ofejecting pistons 15, which are inserted inside said opening withoutprotruding inside channel 7. In the rest of the description and in theclaims, with “initial position” of the pistons will be meant theposition which was just described, occupied by the pistons during thecompression step. The pressure exerted onto the tuna fish portion 12during the compression step is generally not high enough so as to causethe undesired sticking of the foodstuff product to the ejecting pistons15.

[0011] Said portion 12 is then subjected to a shearing step carried outby two dies 16, provided with cutting edges arched as quarters of acircle and positioned behind the back block 5 of the compressing andshaping device. Thus, two semi-finished tuna fish cakes are separated,which are made cylindrical in a subsequent shaping step carried out bymeans of side shaping members 17 slidably arranged inside the two wingsof a channel 18 which perpendicularly intersects compression channel 7.The ends of said side shaping members 17 which are turned towardscompression channel 7 are provided with concavities having asubstantially semi-cylindrical shape. The two wings of channel 18 aresuitably obtained inside the side members 6 of the compressing andshaping device.

[0012] According to the invention, at the same time of the shaping step,the ejecting pistons 15 come out of openings 14 and move backwards withrespect to the compressing and shaping device, away from it. Saidbackward movement of the ejecting pistons has the purpose of lighteningthe pressure of the foodstuff product on their surfaces so as to preventthe undesired sticking.

[0013] Once the above mentioned compressing, shearing and shaping stepsare completed, the tuna fish cakes are ejected from the compressing andshaping device by means of the ejecting pistons 15 which approach againthe compressing and shaping device, penetrate into the compressionchannel through openings 14 and push the tuna fish cakes into two cans18, which are arranged at two openings 19 made in the front block 4. Asliding shutter 20, which has the purpose of preventing the foodstuffproduct from coming out of channel 7 during the compressing and shapingsteps, is raised in order to allow the ejection of the cakes.

[0014] Therefore, the cyclic movement of ejecting pistons 15 comprisesfirst a backward movement starting from said initial position, then aclear forward movement so as to pass through openings 14 and then areturn to the initial position. Said cyclic movement can be controlledby a cam (not shown in the figure) which is driven, for example, by themovement of the side shaping members 17.

[0015] Further advantages and features can be made by those which areskilled in the art to the herewith described and illustrated embodimentby remaining within the scope of the invention.

1. A canning machine for a foodstuff product (2), such as tuna fish andsimilar, comprising a conveyor belt (1) suitable for carrying thefoodstuff product (2) in a compressing and shaping device comprising aknife (11) suitable for cutting substantially parallelepipedal portions(12) of the foodstuff product (2) and a compression channel (7) closedat one end by means of a shaping member (8) and at the other end bymeans of a compactor (9) slidable in the compression channel (7), twoopenings (14) being made in the bottom wall of the compression channel(7) in order to allow the passage of a pair of dies (16) and of a pairof ejecting pistons (15) which in their initial position close saidopenings (14) without substantially protruding into the compressionchannel (7), characterized in that said ejecting pistons (15) have acyclic movement comprising a backward movement with respect to thecompressing and shaping device, a forward movement through said openings(14) and a movement of return to the initial position.
 2. A machineaccording to claim 1, characterized in that said compressing and shapingdevice also comprises a pair of side shaping members (17), slidablyarranged inside the two wings of a sliding channel (18) whichperpendicularly intersects compression channel (7), each side shapingmember (17) having one end provided with a semi-cylindrical concavitysuitable for penetrating into the compression channel (7) by slidingbetween one die (16) and the bottom of the shaping member (8), theoutlet of the two wings of the sliding channel (18) onto the compressionchannel (7) being provided with shutters which can be opened.
 3. Amachine according to the preceding claim, characterized in that thebackward movement of the ejecting pistons (15) occurs at the same timeof the penetration of the side shaping members (17) into the compressionchannel (7).